Move movie runtime support to frontend

docs/PROJECT-STRUCTURE.md

@@ -118,9 +118,9 @@ S:\Game Hacking\Eushully\Himegari\           ← workspace root (three siblings)
     │   ├── Age.Engine/Persistence/          native S3SD/S4SD + S3RT codecs, shared payload/ReadTextDB,
     │                                       layout-3 numbered state/history/gfx, DAT/STH pair + BMP codec,
     │                                       and profile-owned state
-    │   ├── Age.Engine.Frontend/             platform-neutral frontend diagnostics/options project: page
+    │   ├── Age.Engine.Frontend/             platform-neutral frontend support: diagnostics/options, page
-    │                                       locator, timeline/trace/step-limit diagnostics, VM/window launch
+    │                                       location, performance logging, movie decoder/runtime contracts,
-    │                                       options, and performance-frame logging
+    │                                       audio alignment, surface registry, and WAV sanitization
     │   └── Age.Engine.Text.Windows/         optional exact Windows GDI gray-4 reference backend; kept
     │                                       outside the platform-neutral VM/runtime core
     ├── native/                              authored native runtime boundaries
@@ -154,8 +154,10 @@ full-width text entry.
 Both `engine/AgeEngine.sln` and `godot/Himegari.sln` include the project; Godot and `Age.Engine.Tests` consume it
 through project references rather than compiling duplicate linked sources. The first owned cluster contains
 `PageLocatorState`, `GodotTimelineLog`, `GodotTraceSink`, `StepLimitDiagnosticFormatter`, `GodotVmOptions`,
-`PerformanceFrameLog`, and `WindowLaunchOptions`. Movie runtime/decoder helpers remain under `godot/` until their
+`PerformanceFrameLog`, and `WindowLaunchOptions`. It also owns the internal movie decoder boundary/runtime,
-separate ownership slices.
+audio-timeline alignment, movie-surface registry, and RIFF/WAVE sanitizer; only the `Himegari` and
+`Age.Engine.Tests` assemblies receive explicit friend access to that internal API. FFmpeg interop and decoder
+implementation remain under `godot/` until their separate ownership slice.
 
 `godot/GodotAdvHost.cs` retains cross-domain host coordination. Its partial-class companion
 `godot/GodotAdvHost.AdvText.cs` owns live/retained ADV text, surface glyph rasterization and caching,

docs/remake-architecture-and-roadmap.md

@@ -834,6 +834,13 @@ do not mix mechanical moves with semantic changes.
    test source links without changing public types, namespaces, behavior, or export configuration. Both solution
    builds and runtime validation remain green.
 
+   The second bounded build-graph slice moved the unchanged internal movie decoder boundary/runtime, audio
+   alignment policy, movie-surface registry, and RIFF/WAVE sanitizer from `godot/` into `Age.Engine.Frontend`.
+   Five more direct test source links are gone. Explicit friend access is limited to `Himegari` and
+   `Age.Engine.Tests`, so the move preserves the intentionally internal API instead of widening it; FFmpeg remains
+   in Godot while implementing the moved boundary through that friend access. Both solution builds and runtime
+   validation remain green.
+
 5. **Close repository-policy and storage gaps.** Add an explicit project license, third-party notices and
    checksums/provenance for committed binaries, consistent editor/build policy, a pinned .NET SDK, and a
    CI entry point built on the same validation driver. Remove the empty workspace-root `.git` directory and
@@ -1188,9 +1195,9 @@ layer's rendering diverges from ADV; save layout.
 
 ## 8. Immediate next step
 Begin step 4 of the **codebase consolidation** maintenance slice: make the build graph express source ownership
-without changing behavior. Move the platform-neutral movie abstractions and runtime support—decoder interfaces,
+without changing behavior. Move `FfmpegMovieNative.cs` and `FfmpegMovieDecoder.cs` from `godot/` into
-movie/audio runtime state, movie-surface registry, and RIFF sanitization—from `godot/` into
+`Age.Engine.Frontend` next. Replace both test source links and the movie corpus gate's native-source link with
-`Age.Engine.Frontend` next. Replace their test source links while preserving the intentionally internal API through
+project references, granting narrowly scoped friend access to the corpus-gate assembly while preserving native
-explicit friend-assembly access; leave FFmpeg interop/decoder ownership for the following slice.
+ABI, decoder pacing, failure, and teardown behavior.
 Concrete playthrough blockers may still preempt this bounded maintenance work; the consolidation effort does
 not replace Phase B gameplay validation or the open cross-platform gates.

engine/Age.Engine.Frontend/Properties/AssemblyInfo.cs

@@ -0,0 +1,4 @@
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("Age.Engine.Tests")]
+[assembly: InternalsVisibleTo("Himegari")]

engine/Age.Engine.Tests/Age.Engine.Tests.csproj

@@ -24,13 +24,8 @@
     <ProjectReference Include="..\Age.Engine\Age.Engine.csproj" />
     <ProjectReference Include="..\Age.Engine.Frontend\Age.Engine.Frontend.csproj" />
     <ProjectReference Include="..\Age.Engine.Text.Windows\Age.Engine.Text.Windows.csproj" />
-    <Compile Include="..\..\godot\IMovieDecoder.cs" Link="IMovieDecoder.cs" />
-    <Compile Include="..\..\godot\MovieRuntime.cs" Link="MovieRuntime.cs" />
-    <Compile Include="..\..\godot\MovieAudioTimeline.cs" Link="MovieAudioTimeline.cs" />
     <Compile Include="..\..\godot\FfmpegMovieNative.cs" Link="FfmpegMovieNative.cs" />
     <Compile Include="..\..\godot\FfmpegMovieDecoder.cs" Link="FfmpegMovieDecoder.cs" />
-    <Compile Include="..\..\godot\MovieSurfaceRegistry.cs" Link="MovieSurfaceRegistry.cs" />
-    <Compile Include="..\..\godot\RiffWaveSanitizer.cs" Link="RiffWaveSanitizer.cs" />
     <Compile Include="..\..\tools\movie-corpus-gate\MovieCorpusGate.cs" Link="MovieCorpusGate.cs" />
   </ItemGroup>